Open AccessDrag reduction on hydrophobic transverse grooved surface by underwater gas formed naturally
Author(s) -
Bao Wang,
Jiadao Wang,
Darong Chen
Publication year - 2014
Publication title -
wuli xuebao
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.199
H-Index - 47
ISSN - 1000-3290
DOI - 10.7498/aps.63.074702
Subject(s) - drag , materials science , perpendicular , transverse plane , surface (topology) , surface roughness , surface finish , flow (mathematics) , mechanics , optics , composite material , physics , geometry , mathematics , structural engineering , engineering
Low fluid friction is difficult to obtain on super-hydrophobic surfaces for a large flow velocity, because the entrapped gas within the surface is weakened substantially. Once the gas removed, the friction of the fluid increases markedly due to its own surface roughness. In this study, a hydrophobic transverse microgrooved surface is designed to sustain the air pockets in the valleys for a long time. Direct optical measurements are conducted to observe the entrapped gas when water flows past the surface in the perpendicular direction of grating patterns. More importantly, this hydrophobic transverse micro-grooved surface has been determined to have the capability of automatic formation of gas. Some of the gas is continually carried away from the surface and new gas is continually generated to substitute the lost gas. And the stable slippages at the surface are achieved corresponding to the relative stable gas on this designed surface.